An update on the interview with David Tschumperlé

Alexandre Prokoudine, who translated David’s interview in Russian, asked for some more precisions from David regarding using GREYCstoration to denoise a RAW image before dematricing. That is the approach that DXO 5 uses, apparently with very good results. Here is the extract:

AP: Can GREYCstoration actually be used before Bayer reconstruction already or with some (what exactly?) changes in the future?

DT: Concerning the RGB Bayer reconstruction, I already tried to adapt the PDE’s used in GREYCstoration to handle this case, but without much success. I guess GREYCstoration can be used as a post-process perhaps to remove some reconstruction artefacts, but I don’t see a serious way to use it before the reconstruction step.

Concerning the future changes, I have actually a lot of ideas and an on-going research work that could be integrated in GREYCstoration. I’m writing a research paper to describe all these techniques. Once this paper is accepted for publication in a conference, I plan to integrate those stuffs as soon as possible.

Since then, a new version of GREYCstoration ( 2.8 ) has landed; it has a new denoising method called “patch-based” which offers, according to David’s announcement “quite interesting denoising results when parameters are set correctly, sometimes better than with the traditional ‘-denoise’ method.” It is based on this research paper by David.

The 2.8 version of GREYCstoration offers a patch denoising option in the command line and in the Linux based Gimp plug-in. So far, my testing hasn’t proved ground-breaking; no significant enhancement compared to what can be achieved with “normal” denoising. But setting parameters correctly isn’t a very easy task so I may have missed something.


4 Responses to An update on the interview with David Tschumperlé

  1. Alexandre says:

    Hi, I actually spoke with Dave Coffin at LGM (and mentioned your blog :)) about the whole thing and he told me that denoising in DCRaw works before demosaicing 🙂

  2. jcornuz says:

    Hi Alexandre,

    Thanks for this comment. I had totally overlooked the presentation of Dave Coffin – it was really informative to watch his talk.

    Take care,


  3. Elisa says:

    Normally I do not read post on blogs, however I would like to say that this write-up very pressured me to take a look at and do it! Your writing taste has been amazed me. Thanks, very great article.

  4. Hello there! This article could not be written any better!
    Looking at this article reminds me of my previous roommate!
    He continually kept preaching about this. I will send this information to him.
    Fairly certain he’s going to have a great read. Many thanks for sharing!

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )


Connecting to %s

%d bloggers like this: